Involvement of 5-HT3 and 5-HT4 receptors in colonic motor patterns in rats

BACKGROUND

Colonic migrating motor complexes in the rat constitute two distinct propulsive motor patterns, pan-colonic rhythmic long distance contractions (LDCs), and rhythmic propulsive motor complexes (RPMCs) occurring primarily in the mid/distal colon. Interstitial cells of Cajal govern their rhythmicity, but their occurrence is dependent on neural programs. Our aim was to investigate the involvement of 5-HT3 and 5-HT4 receptors in the generation and pharmacological control of the motor patterns.

METHODS

Effects of 5-HT-related drugs on colonic motor patterns were analyzed through spatio-temporal maps created from video recordings of whole organ motility.

KEY RESULTS

5-HT3 antagonists abolished RPMCs and LDCs. 5-HT4 agonists inhibited LDCs; they promoted RPMCs, which was blocked by the 5-HT4 antagonist GR 125487. 5-HT and the 5-HT3 agonist m-CPBG strongly inhibited LDCs and RPMCs.

CONCLUSIONS & INFERENCES

The generation of LDCs involves ongoing 5-HT release acting on 5-HT3 and 5-HT4 receptors. The spontaneous generation of RPMCs involves ongoing 5-HT release acting on 5-HT3 but not 5-HT4 receptors. Prucalopride and mosapride promote RPMCs, an effect that is inhibited by the 5-HT4 receptor antagonist GR 125487. A 5-HT3 agonist does not promote RPMCs. Segmentation, including a pattern of sequential segmental activity not previously described, can occur without significant involvement of 5-HT3 and 5-HT4 receptors. 5-HT and a 5-HT3 agonist are strongly inhibitory indicating that 5-HT receptors are present in inhibitory pathways which are normally not involved in the generation of spontaneous or distention-induced motor patterns.

Association between etiologic factors in infertile couples and fertilization failure in conventional in vitro fertilization cycles

The aim of this study was to investigate the relationship between the etiology of the couples and risk of fertilization failure (FF) in conventional in vitro fertilization (IVF) cycles and the effect of rescue intracytoplasmic sperm injection (ICSI) technique to offspring. A total of 2542 IVF cycles were divided into four groups according to infertile etiology: Group A - primary infertility with normal semen parameters; Group B - secondary infertility with oligoasthenozoospermia; Group C - primary infertility with oligoasthenozoospermia; and Group D - secondary infertility with normal semen parameters. The results showed that there were significant differences in incidence of FF among Group A (16.8%), Group B (20.9%), Group C (48.7%), and Group D (0.9%) (p < 0.001). Logistic regression models demonstrated that primary infertility (OR: 10.898, 95% CI: 4.651-25.583, p < 0.001) and oligoasthenozoospermia (OR: 12.215, 95% CI: 5.903-25.276, p < 0.001) were independent risk factors for FF. There were no significant differences in main outcomes between conventional ICSI and rescue ICSI. In conclusion, the patients with primary infertility and oligoasthenozoospermia might be at higher risk of FF. The rescue ICSI technique is safe and helpful for IVF cycles of FF.

Ultrasensitive graphene far-infrared power detectors

We describe the properties of ultrasensitive graphene photon detectors for use in the far-infrared/terahertz spectral region and present theoretical predictions for their power detection sensitivity. These predictions are based on two graphene contacting schemes with superconducting contacts: contacts with a thin insulating barrier, and direct superconducting contacts. To quantitatively assess these predictions, we perform thermal measurements of graphene at low temperatures and analyse them to extract information on electron-phonon cooling in graphene. These new results for the electron-phonon cooling channel allow reliable prediction of the noise equivalent power (NEP) that can be expected from an optimized graphene detector, using measurement of the Johnson noise emission as the thermometry method. We find that an NEP of 2 × 10(-19) W Hz(-1/2) should be achievable under certain biasing conditions with an ideal device.

Alterations in frontal white matter neurochemistry and microstructure in schizophrenia: implications for neuroinflammation

We investigated in vivo neurochemical markers reflective of neuronal health and glial activation to determine if these could yield clues regarding the reduced fractional anisotropy (FA) of white matter and accelerated decline of FA with age in schizophrenia. Participants with schizophrenia and healthy controls completed diffusion tensor imaging to assess FA and proton magnetic resonance spectroscopy to assess neurochemical metabolites in the same frontal region. Frontal FA was significantly lower in the schizophrenia and declined more rapidly with age compared with the healthy control group. In both groups, N-acetylaspartate (NAA), a putative marker of neuronal integrity, and glutamate declined with age, and this decline was stronger in patients. Myo-inositol, a marker of glial cells, was negatively related to FA in both groups. The relationship between FA and age remained significant in schizophrenia even when controlling for all metabolites. The relationships of FA, NAA and myo-inositol to age appear to be independent of one another. The relationship between FA and myo-inositol was independently present in both patients and controls, even after controlling for age, indicating a potential general effect of neuroinflammation on white matter microstructure. Further studies are warranted to determine the underlying mechanism driving the accelerated FA decline with age in schizophrenia.

Cohn process influences the functional anticoagulant activity of human protein C

Cohn fraction IV (CFIV) is a byproduct of a plasma fractionation process known as the Cohn process. It is an inexpensive source of protein C, retaining about 90% of protein C (PC) in human plasma. We investigated whether PC is affected during the Cohn process and evaluated correlations among coagulant activity, amidolytic activity and PC antigen during the Cohn process. CFIV was redissolved with citrate-buffered saline for 5 h at 4°C, and then centrifuged at 3500 g for 40 min at 4°C. Functional anticoagulant activity was measured with a one-stage coagulation method based on activated partial thromboplastin time. The functional amidolytic activity of PC was determined using chromogenic substrate assay, and measurement of PC antigen was performed by ELISA. In CFIV, anticoagulant activity declined significantly, with a loss of >80%, while amidolytic activity was not significantly altered, compared to PC antigen. Prior to the Cohn process, high-rank correlations were observed in cryosupernatant, with rs = 0.921 for anticoagulant and amidolytic activities (P = 0.009), 0.896 for anticoagulant activity and antigen (P = 0.014) and 0.832 for amidolytic activity and antigen (P = 0.031). After the Cohn process in CFIV, there was also a high correlation between amidolytic activity and antigen (rs = 0.782, P = 0.038). There were no significant correlations between anticoagulant activity and antigen (rs = 0.223, P = 0.653), or anticoagulant and amidolytic activity (rs = 0.236, P = 0.675). We conclude that the Cohn process significantly influences the anticoagulant activity of PC. Compared to the antigen, PC lost greater than 80% of its anticoagulant activity, but retained its amidolytic activity, during the Cohn process.

Three novel single nucleotide polymorphisms of the 3-hydroxy-3-methylglutaryl coenzyme A reductase gene associated with egg-production in chicken

Different single-strand conformation polymorphism (SSCP) patterns of the 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) gene amplified by six pairs of primers were sequenced. Comparisons among the six nucleotide sequences of three genotypes revealed three base substitutions (G-789-A, C-937-G, and A-2316-C) in the HMGCR gene. The genotypes of single nucleotide polymorphism 1 (SNP1) and SNP3 were significantly associated with the number of eggs (P < 0.01), and the different genotypes of SNP2 did not significantly influence the number of eggs. The genotypes of all three SNPs were not related to the hatching rate of fertilized eggs (P > 0.05). Of the three SNPs of the HMGCR gene, those genotypes with lower plasma very low-density lipoprotein (VLDL) concentrations had higher egg production. The 300-day egg production of the six studied haplotypes showed three levels (P < 0.01). The ADE and ACE haplotypes showed lower egg production than the other haplotypes. The ADE haplotype had the highest plasma VLDL concentration, and the ACE haplotype had the lowest plasma VLDL concentration. We concluded that specific variants of the HMGCR gene are associated with chicken egg production, and haplotypes with higher and lower plasma VLDL concentrations showed lower egg production than other haplotypes.

Effects of acid dopants on the capacitance of polyaniline by using graphene hydrogels as substrates

Acids have a great impact on the specific capacitance of polyaniline, and graphene/polyaniline (GP) doped with H₂SO₄possesses the highest capacitance compared with that of GP–HCl and GP–HClO₄.

Catalytic dehydrogenation of propane by carbon dioxide: a medium-temperature thermochemical process for carbon dioxide utilisation

The dehydrogenation of C₃H₈ in the presence of CO₂ is an attractive catalytic route for C₃H₆ production. In studying the various possibilities to utilise CO₂ to convert hydrocarbons using the sustainable energy source of solar thermal energy, thermodynamic calculations were carried out for the dehydrogenation of C₃H₈ using CO₂for the process operating in the temperature range of 300–500 °C. Importantly, the results highlight the enhanced potential of C₃H₈ as compared to its lighter and heavier homologues (C₂H₆ and C₄H₁₀, respectively). To be utilised in this CO₂ utilisation reaction the Gibbs free energy (Δ_rGθm) of each reaction in the modelled, complete reacting system of the dehydrogenation of C₃H₈ in the presence of CO₂ also indicate that further cracking of C₃H₆ will affect the ultimate yield and selectivity of the final products. In a parallel experimental study, catalytic tests of the dehydrogenation of C₃H₈ in the presence of CO₂ over 5 wt%-Cr₂O₃/ZrO₂ catalysts operating at 500 °C, atmospheric pressure, and for various C₃H₈ partial pressures and various overall GHSV (Gas Hourly Space Velocity) values. The results showed that an increase in the C₃H₈ partial pressure produced an inhibition of C₃H₈ conversion but, importantly, a promising enhancement of C₃H₆ selectivity. This phenomenon can be attributed to competitive adsorption on the catalyst between the generated C₃H₆ and inactivated C₃H₈, which inhibits any further cracking effect on C₃H₆ to produce by-products. As a comparison, the increase of the overall GHSV can also decrease the C₃H₈ conversion to a similar extent, but the further cracking of C₃H₆ cannot be limited.

Analyzing the influence of BDNF heterozygosity on spatial memory response to 17β-estradiol

The recent use of estrogen-based therapies as adjunctive treatments for the cognitive impairments of schizophrenia has produced promising results; however the mechanism behind estrogen-based cognitive enhancement is relatively unknown. Brain-derived neurotrophic factor (BDNF) regulates learning and memory and its expression is highly responsive to estradiol. We recently found that estradiol modulates the expression of hippocampal parvalbumin-positive GABAergic interneurons, known to regulate neuronal synchrony and cognitive function. What is unknown is whether disruptions to the aforementioned estradiol-parvalbumin pathway alter learning and memory, and whether BDNF may mediate these events. Wild-type (WT) and BDNF heterozygous (+/-) mice were ovariectomized (OVX) at 5 weeks of age and simultaneously received empty, estradiol- or progesterone-filled implants for 7 weeks. At young adulthood, mice were tested for spatial and recognition memory in the Y-maze and novel-object recognition test, respectively. Hippocampal protein expression of BDNF and GABAergic interneuron markers, including parvalbumin, were assessed. WT OVX mice show impaired performance on Y-maze and novel-object recognition test. Estradiol replacement in OVX mice prevented the Y-maze impairment, a Behavioral abnormality of dorsal hippocampal origin. BDNF and parvalbumin protein expression in the dorsal hippocampus and parvalbumin-positive cell number in the dorsal CA1 were significantly reduced by OVX in WT mice, while E2 replacement prevented these deficits. In contrast, BDNF(+/-) mice showed either no response or an opposite response to hormone manipulation in both behavioral and molecular indices. Our data suggest that BDNF status is an important biomarker for predicting responsiveness to estrogenic compounds which have emerged as promising adjunctive therapeutics for schizophrenia patients.

Explanation of colon cancer pathophysiology through analyzing the disrupted homeostasis of bile acids

BACKGROUND

The colon plays a key role in regulating the homeostasis of bile acids.

AIM

The present study aims to evaluate the influence of colon cancer towards the homeostasis of bile acids.

METHODS

The free and conjugated bile acids were determined using ultraperformance LC (UPLC) coupled with ABI 4000 QTRAP triple quadrupole instruments.

RESULTS

The results showed that the free bile acids in serum of patients with colon cancers tend to increase, and the conjugated bile acids tended to decrease, especially for taurolithocholate (TLCA) (p<0.001).

CONCLUSION

The alteration of bile acids balance in colon cancers indicated the possibility of complicated diseases due to the disrupted balance of bile acids.

HbA1c levels as predictors of ablation outcome in type 2 diabetes mellitus and paroxysmal atrial fibrillation

AIMS

The aim of this study was to evaluate whether the levels of HbA1c could predict the outcome of ablation in patients with type 2 diabetes mellitus (T2DM) and paroxysmal atrial fibrillation (PAF).

PATIENTS AND METHODS

The study comprised 149 consecutive patients with T2DM and PAF who underwent their first circumferential pulmonary vein isolation. HbA1c levels were measured before ablation. Cox proportional hazards models were constructed to assess the relationship between HbA1c levels and the recurrence of atrial fibrillation (AF).

RESULTS

Of the 149 patients, 60 (40.3 %) developed AF recurrence after a median 12-month follow-up. Multivariate Cox regression analysis revealed that left atrium size and HbA1c were independent predictors of recurrent atrial tachyarrhythmia. Receiver operating characteristic analysis demonstrated that an HbA1c cut-off value of ≥ 6.9 % predicted recurrence with 55.0 % sensitivity and 67.4 % specificity (AUC = 0.634). The success rate of ablation was 69.0 % in patients with an HbA1c value of < 6.9 % compared with 46.8 % in those with an HbA1c value of ≥ 6.9 % (log-rank test, p = 0.004).

CONCLUSION

High levels of HbA1c were associated with an increased risk of recurrence of atrial tachyarrhythmia in patients with T2DM and PAF undergoing catheter ablation.

The influence of the HPG axis on stress response and depressive-like behaviour in a transgenic mouse model of Huntington's disease

Huntington's disease (HD) is an autosomal dominant, neurodegenerative disease caused by a CAG tandem repeat mutation encoding a polyglutamine tract expansion in the huntingtin protein. Depression is among the most common affective symptoms in HD but the pathophysiology is unclear. We have previously discovered sexually dimorphic depressive-like behaviours in the R6/1 transgenic mouse model of HD at a pre-motor symptomatic age. Interestingly, only female R6/1 mice display this phenotype. Sexual dimorphism has not been explored in the human HD population despite the well-established knowledge that the clinical depression rate in females is almost twice that of males. Female susceptibility suggests a role of sex hormones, which have been shown to modulate stress response. There is evidence suggesting that the gonads are adversely affected in HD patients, which could alter sex hormone levels. The present study examined the role sex hormones play on stress response in the R6/1 mouse model of HD, in particular, its modulatory effect on the hypothalamic-pituitary-adrenal (HPA) axis and depression-like behaviour. We found that the gonads of female R6/1 mice show atrophy at an early age. Expression levels of gonadotropin-releasing hormone (GnRH) were decreased in the hypothalamus of female HD mice, relative to wild-type female littermates, as were serum testosterone levels. Female serum estradiol levels were not significantly changed. Gonadectomy surgery reduced HPA-axis activity in female mice but had no effect on behavioural phenotypes. Furthermore, expression of the oestrogen receptor (ER) α gene was found to be higher in the adrenal cells of female HD mice. Finally, administration of an ERβ agonist diarylpropionitrile (DPN) rescued depressive-like behaviour in the female HD mice. Our findings provide new insight into the pathogenesis of sexually dimorphic neuroendocrine, physiological and behavioural endophenotypes in HD, and suggest a new avenue for therapeutic intervention.